Stress and strain compensating joint for rotary well-drilling columns



Dec. 16, 1930. A. J. PONTI 1,785,559 STRESS AND STRAIN COMPENSATING JOINT FOR ROTARY WELL DRILLING COLUMNS Filed 001;. 28. 1927 LWA/ T/// [N VENTOR ART/J01? J/"owrz Patented Dec. 16, 1930 NITED STATES ARTHUR J. PONTI, OF LOS ANGELES, CALIFO STRESS AND STRAIN COMPENSATING JOINT FOR ROTARY WELL-DRILLING GOLUHIWQ Application filed October 28, 1927. Serial No. 229,388.

This invention relates to a device applicable to the tubular columns of rotary well-drilling apparatus.

In southern California oil wells are drilled by rotary rigs to great depths, there being many oil producing wells over six thousand feet in depth, and a number of wells ranging from six thousand five hundred feet to eight thousand feet deep.

Such holes are drilled by means of a tubular bit on the lower end of a tubular drill stem or column that is rotated in the hole while there is pumped down through the column and the bit, a flow of what is known to the drillers as fluid or liquid rotary drilling mud which is depended upon to remove the drillings from the bottom of the hole and to carry such drillings'up outside the drill bit and rotary column to the surface where it is discharged; the flow of such mud being continued so long as the drill is rotated.

The rotary tubular drilling columns for such depths are necessarily ponderous, and very powerful machinery is employed to move them vertically and such movement subjects the machinery, the derrick and the column to great jars, shocks, stresses and strains, likely to cause breakage of the machinery, and the column, and to rack and break the derrick, and great expense and loss of time for repairs is likely to be imposed thereby.

Such jars, shocks, stresses and strains are also likely to cause crystallization of the rotary drill column, especially at the joints, whereby such column may give way unexpectedly under comparatively light service.

It has been proposed to interpose in the hollow rotary drill column a joint provided with means for absorbing the shock.

An object of this invention is to provide an anti-collapsing appliance that when interposed in the column, will absorb the shock or will yieldingly transmit the force applied to move the column vertically, and that will make provision whereby the appliance may be installed to operate at any depth required for practical use.

Another object is to so construct the column joint that it will hold the tubular stem sectionsin true alinement and free from any wobbling. i

In carrying out this invention it is necessary to guard against any likelihood that the hydrostatic pressure on the outside of the joint will collapse the same.

Another object is to make provision whereby any tendency toward the horing of a crooked hole will be neutralize-d or avoided.

It has been roposed to make a rotary column out of tu ular rotary stem sections having a central bore and united by threaded box and pin joints, and in this invention I introduce into such column in relative non-rotating relation, a tubular housing having closed ends, and two stem sections reciprocahle through such ends and provided in the housing chamber, with heads separated from each otherand from the housing heads by yielding means that will modify the relative axial movement of the heads of the housing and the stem' section, and there intercept or modify thewshock; and I have interposed springs between the heads of stems and housing for this purpose and for the purpose of resiliently spacing the heads apart to allow requisite reciprocatory movement of the parts without actual contact of the heads, or such abrupt termination of the reciprocatory movement of the parts as would result in a destructive jar either up or down, but to allow application of momentum of the column to loosen a stuck tool from the walls of the hole.

I also provide for a sliding fit between the peripheries of the stem section heads and the bore of the housing, and a like sliding fit of the stems with the housing heads and rovide stufling boxes in the housing hea s to prevent leakage of the liquid mud from the housing and rovide-for flow of mud from spring cham er to spring chamber to accommodate such relative movement of the stem heads as may be required.

By preference, the housing diameter approximates, but is somewhat less than that of the rotary drill bit so that while the housing rotates freely inside the drilled hole, it cannot swing to any great extent without contacting the walls of the hole; and the 1911 h of the housing is considerable so that de ection of the bit from the vertical will be prevented or corrected by contact of the rotating housing with the wall of the hole.

This invention comprises a tubular rotary I drilling column provided with axially alined relatively reciprocable tubular drill stem sections having heads, and a shell non-rotatable relative to the stem sections and provided with a chamber inclosing the headed terminals of the stem sections; means inside the chamber for yieldingly separating the heads from each other and for separating the heads from the ends of the chamber; the bores of said drill stem sections being open to the chamber so that drilling mud may flow through and fill the column and the telescopic joint; and so that hydrostatic pressure of the drilling mud will be applied inside the joint to balance the hydrostatic pressure outside the joint during operation of the drill.

In order .to prevent collapse of the joint shell it is necessary that the shell be filled with liquid under hydrostatic pressure corresponding to that in the hole, so that the hydrostatic pressure on thejnside of the column will correspond to that on the outside of the column.

An object of this invention is to provide a pressure equalizing, and stress and strain compensating, joint for rotary well drilling columns.

Another object of the invention is to make provision whereby the operation of the drillmg apparatus will practically insure a straight hole.

'This invention is broadly new, basic and pioneer in that it comprises a coupling shell in combination with two headed telescopic drill stem sections axially alined therewith and provided'with bores opening into the shell, and shock absorbing means to resiliently position the ends of the drill stem and sections with'relation to each other and to the headsof the shell.

' Advantages incident tothe use of the device of my invention are greater ease of tool handling; more even feed of the drilling bit;

obviation of breaka e the the joints in the pipe'column and in t e handling mechanism; the ability to spud the drill without injury to the drill on pipe column and in the avoi showing the stem, stufiing box and split ring nut.

Fig. 4 is a cross section on line :12, Fig. 2.

Fig. 5 is a cross section on line m Fig. 2.

Arrows on line m :0, and {1: indicate the direction of sight.

1 designates the drilling tool, having bits 2, and carried on the lower drill pipe section 3 and operated in a common manner b rotation of the drill pipe or stem from t e surface and by forcing water under ressure through the pipe to the point of drilling.

The character 4 in Fig. 1, indicates the lower portion of a hole being drilled by a bit operated by the rotary tubular drill stem made up of sections having pin and box connections as at 5 and 6 in Figs. 1 and 2.

The compensating'joint comprises a housin 7 which consists of a length of metallic tubing having internal screw threads 8 at each end to receive the stuffing boxes 9 and 10, the outer peripheries of which include a length, bearing external threads 11 for engagement with the threads 8 of the housing and have their remaining lengths formed 00- tagonal, or otherwise to provide seats for turning, as by a wrench, or similar tool.

Formed axially throu h each stufiing box is a hole12 of non-circ ar contour, such as the hexagon shown, and extended through each stuffing box is a stem 13, sectionally shaped to conform with hole 12 of the stuffing box and dimensioned to freely slide therethrough. The upper end of the stem projecting from the top of the housing is provided with an internally threaded socket 1 1, similar to the described sockets 6, and the lower'end of the stem projecting from the bottom of the housing is provided with a threaded reduction 15, similar to the described reductions 5, whereby the stems may be coupled in the pipe column bybox and pin similarly to its several pipe lengths.

Each stem carries at its end within the housing a circular head 16 having a diameter substantially that of the internal diameter of the housing and the stem and head are formed with a continuous passageway 30. for

communication with the interiors of the adjoining pipe lengths of thecolumn.

By preference, and as shown, the heads are formed as integral parts of the stems, as by forging or casting.

Interposed between and impinging the stufiing box 9 and the head of the upper stem; within the housing and surrounding the stem is an extensile, or compression sprin 18.

Similarly between and impinging the stuffing box 10 and head of the lower stem is an extensile, or compression, spring 19 having substantially the same tension as the spring 18, and for impingement between the two heads is an extensile, or compression, spring 20 having a weight and tension greatly in excess of the springs 18 and 19.

In each stuifing box there is formed a gland 21, to receive packing around the stem, and

pletely fills the gland over the packing. .The

body portions of the follower are spaced from the wall of the land to receive therebetween a gland nut 24 in the form of an open ring, externally threaded for engagement with threads 25 in the outer part of the gland and provided with means such as the slots 26 for a tool such as a spanner, for turning the nut to tight or loose fits over the packing follower.

In drilling through certain formations, there is a condition known as balling which fouls the tool bits and renders them inoperative and a common remedy for this condition is to spud the tool, which consists in raising the tool and dropping it violently upon the bottom of the hole. In other formations there'is a condition known as sticking in which the formation by adhesion prevents or interferes with tool operation, a common remedy for which is jerking the tool. Obviously both of such operations impose enormous stresses in the pipe column and frequently result in breaking the pipe column especially at its threaded joints or bending the column to inoperative condition.

By reason of the parted stems forming a break in the pipe column and the springs acting on and between the parted stems, all longitudinal stresses tending to break, bend, or otherwise injure the pipe column are relieved.

The bore of the housing is divided by the head 16 of the tubular drill stem sections into upper, lower and intermediate bufler chambers 27, 28, 29, and said chambers are in communication with each other as by loose fit of the heads 16 and 17 and passages 30 in the telescopic sections 13 of the drill stem, thus allowing movement of the heads relative to each other and to the closed ends of the housing 7.

The housing with its hydrostatically filled chamber forms an anti-collapsing guiding enlargement of the drill stem adapted to be guided in a vertical course by contact with the wall of the hole, thus to facilitate or insure drilling a straight hole.

In addition to such mechanical compensation there is hydraulic cushioning provided by the housing filling with water especially in the space between the heads of the stems and the relative movement ofthe stems is governed by the impeded movement of the I claim 1. In a drilling apparatus, a pipe column comprising in its length a telescopic jo nt provided with means for compensating longitudinal stresses in the column, and means for applying hydrostatic pressure inside the joint to counter-balancethe hydrostatic pressure outside the joint during drillin 5 In adrilling apparatus, an element for couplin in the pipe column, comprising means or compensating longitudinal stresses in the column; and for equalizing inside and outside hydrostatic pressures on such column.

water fromsuchspace, through the. relativesmaller holes in the stems.

3. A rotary drilling column provided with I axially alined relatively reciprocable tubular drill stem sections having heads, and a shell non-rotatable relative to the stem sections, and provided with a chamber inclosing the headed terminals of the stem sections; means inside the chamber for yieldingly separating the heads from each other and yieldingly separating the heads from the ends of the chamber; the bores of said drill stem sections being open to the chamber so that drilling mud may flow through and fill the column and the telescopic joint and so.

that the hydrostatic pressure inside and outside the joint will balance each other.

4. In a rotary drill column, a housing in combination with two drill stem sections having heads and being axially alined with each other and with the housing and telescoping with relation to the housing and provided with bores opening into the housing; and shock absorbing means to resiliently position the heads of the stems relative to each other and to the housing.

5. In a rotary well drill column, the combination with headed drill stem sections, of a housing non-rotatable relative to said sections and having closed ends through which the drill stem sections reciprocate, and the heads of which are movable inside and are open to the inter-head space in the housing; and springs inside the housing to yieldingly separate the stem heads from each other and from the heads of the housing.

6. A rotary drill column provided with headed hollow rotary stem sections and a housing in which the headed portions of said section are non-rotatably and reciprocably mounted and adapted to supply fluid mud under hydrostatic pressure to guard against collapse of the housing.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 20th 

